It is well-known that local timing signals in a digital receiver must be synchronized to an incoming digital signal in order to recover the data. Heretofore, such timing signals were recovered from the incoming digital signal by employing a phase locked loop. The phase locked loop was responsive to the incoming digital signal for generating a phase error signal which, in turn, controls a voltage controlled oscillator to generate a local timing signal.
In frames of certain incoming digital signals, there are additional overhead bit positions and so-called stuffing bit positions which when eliminated leave gaps in the data stream. Because of such gaps, the recovered timing signal generated by a typical phase locked loop arrangement is not smooth causing jitter. As is well-known, jitter is extremely undesirable in timing signals. Additionally, it is desirable that the generated timing signal follow variations in the incoming digital signal caused by the stuffing bits.